Tunnel liner



y 2, 1940. J. L. GILLMAN, JR 2,206,825

TUNNEL LINER Filed Jan. 15, 19 34 Patented July 2, 1940 UNITED STATES PATENT OFFlCjE TUNNEL LINER Joseph L. Gilllnan, Jr., Youngstown, Ohio, assign I or to The Commercial Shearing & Stamping Company, Ohio Youngstown, Ohio, a corporation of 3 Application January 15, 1934, Serial. No. 706,585

2 Claims. (01. 61-45) My invention relates to linings for earth borings, such as tunnels and, in particular, to linings assembled from a shape.

j If it werepossible to design tunnels with the ideal shape and to subject the steel linings thereof. to an ideal arrangement of loads, the segments composing the lining would be in pure compression. Under such conditions, conselquently, the form of a segment would helm-- material except for convenience in handling and attaching. It has been the practice heretofore to position metal segments of substantially rectangular shape in tunnel linings with one edge parallel to the tunnel axis. Difficulty is sometimes experienced under this arrangement in alining successive plates adjacent their neighbors in positionto be attached thereto. The segments are curved along one edge to conform to the curvature of the assembled lining. Under the conditions of actual practice, furthermore, the ideal shape of tunnel section and the ideal distribution of loads are seldom encountered, with the result that the segments are subjected to'severe bending moments. It is the existence of these bending moments that makes it necessary to consider carefully the form. and arrangement of liner segments. It is known that the joints. between segments are particularly deficient in moment-carrying capacity.

' I have invented a liner segment which provides a lining with greater resistance to bending moments than has been attainable with segments as previously made. In accordance with my invention, I so position the segments that all their edges are at an. angle to the tunnel axis. I preferably make them of substantially diamond-shape and assemble them in rings in a manner somewhat similar to that previously used for rectangular segments, the points of the segments of one ring interfitting with the points of the segments of adjacent rings. The shape of the segments, furthermore, facilitates their installation in the lining. It is well known that it is easier to make a good fit between correspondingly tapering elements than between elements having parallel or abutting engaging plurality of sections of similar the exterior of a tunnel lining in accordance with my invention; I

Figure 2 is a plan view of the exterior of one of the segments;

Figure 3 is a sectional View along the line III-III of, Figure 2 showing the disposition of i flange ll extending about the periphery thereof.

The body portion I2 of the plates is formed transversely to conform to the curvature of the lining. Bolt holes l3 are provided in the flanges whereby adjacent segments may be connected by bolts l4.

As will be apparent in Figure l, the segments are arranged in discontinuous rings around the circumference of the tunnel, the segments of successive ringsbeing ofiset and having their points interfitting. The segments of successive w rings, of course, are disposed in helices. This construction, obviously, is one of great strength and particularly high resistance to bending moments, as will be shown more explicitly later.

The shape of the segments, furthermore,

facilitates their assembly with the previously erected segments. It is quite a simple matter to direct a non-rectangular segment into the V betweentwo previously erected segments and attach the former to the latter. This operation .52

is somewhat simpler than the installation of segments of rectangular shape. The segment may, of course, be bent along the long diagonal as well as along the short diagonal, as shown.

E'ach transverse section of a tunnel lining has a definite load-carrying capacity; While it is possible to consider that each longitudinal section, or each section between parallel helices, has a definite share of the load to carry, but since the greatest strength per pound of metal is derived from short-span sections, the transverse sections are considered to carry the entire load. In tunnel linings constructed by assembling segments with one edge parallel to the longitudinal axis of the tunnel, which will be designated hereinafter as Type A, the transverse moment carrying. capacity is obtained by thefollowing formula: I

ZE:.50ZP+.50ZJ where ZE is the total efiective section modulus, Zp is the plate section modulus and ZJ the joint section modulus, all for unit length of the lining,

In tunnel linings constructed in accordance with my invention, hereinafter designated as Type B, where no edge of a segment is parallel to the axis of the tunnel, the transverse momentcarrying capacity is given by the following formula: ZE=ZP in which the symbols have the meaning explained hereinabove.

In order to effect a failure of a tunnel lining of type A by transverse bending, it is necessary only to bend alternate plates through the flanges and the intermediate plates at the joints. In tunnel linings of type 13, every plate must bend through the flanges. In a lining of type A, for example, to effect a transverse failure over a longitudinal distance of two segment widths, only two flanges would have to fail. In other words, there would have to be a failure of one plate and one joint. In a lining of type B, however, two plates or four flanges would have to fail for each longitudinaldistance equal to two segment widths. Assuming a joint capacity of about 10% to moment-carrying capacity, which is probably a conservative estimate, the two types would compare as follows in resistance to bending stress:

It will be apparent from the foregoing that the resistance of the lining of my invention to bending stress is nearly twice as great as that of tunnel linings previously constructed.

It is obvious that any improvement in joint efficiency would tend to make the previous arrangement (type A) more nearly the equal of my invention (type B). Practical limitations, however, appear to prevent the design of a joint with an efficiency in excess of about 25%. My inven tion, therefore, appears to offer considerably greater promise for strengthening the tunnel linings against bending stress than any possible modification of present types of joints between segments with one edge parallel to the tunnel axls.

It is not necessary that the segments of my invention be symmetrical about either diagonal or any other axis, or that they have the outline of a parallelogram or quadrilateral. Examples of shapes of segments other than the diamond shape already described which may be employed in practicing my invention, are illustrated in Figures 4 and 5. In Figure 4, the segments have a substantially diamond shape but are adapted to be positioned with the two opposite edges at right angles to the tunnel axis. The remaining edges, of course, are at an oblique angle to the axis. Figure 5 shows an arrangement of hexa onal segments. In both Figures 4 and 5, as well as in Figure 1, it will be clear that the segments formhelicesaround the lining. In any transverse section through the lining, however, there are a plurality of segments disposed substantially in ring formation, although the segments of each ring are separated by portions of segments of adjacent rings.

The advantages characterizing my invention are not associated with any specific shape of segment but result simply from the disposition of the segments so that there are no edges parallel to the tunnel axis. As previously explained, joints parallel to the axis weaken the lining,

whereas by disposing all joints at an angle to the axis, the lining is considerably strengthened.

In Figure 4 the axis of the tunnel extends crosswise of the sheet, and in Figure 5, lengthwise of the sheet. In both cases, all edges of the segments are at an angle to the axis.

It will be apparent from the foregoing description that the invention is characterized by important advantages over lining segments as previously made. The principal advantages ar; the increase in resistance to bending stress an the increased facilitation of erection. At the same time, the segments of my invention may be manufactured ata low cost so as to compete effectively with previous designs.

Although I have illustrated and described herein but one embodiment of the invention, it will be apparent that numerous changes in the details of the invention as disclosed herein may be made without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. A tubular structure composed of a plurality of abutting substantially diamond-shaped plates, each of said plates having a pair of edges of uniform length converging to a point and forming one pointed end for the plate, and having two other edges of the same length as the aforesaid edges, said two other edges also converging to a point and forming a second pointed end for the plate, the points of said ends of each plate being disposed in a plane at right angles to the length of said structure, all of said edges being provided throughout their lengths with lateral flanges, and bolts securing the flanges of the various plates together, whereby half the number of said flanges are pitched in one direction and the other flanges are pitched in the other direction, said plates being so positioned that any of said flanges of any plate lies throughout its length against the full length of an adjacent flange of an adjacent plate, whereby half the number of said flanges jointly form continuous reinforcing members pitched form continuous reinforcing members pitched to 1 the same extent in the other direction to effectively brace the structure.

2. A tubular structure composed of diamondshaped plates disposed in annular series with the pointed ends of the plates of any series disposed in a single plane at right angles to the axis of the tubular structure, the plates of any of said annular series being in abutting relation with the plates of the adjacent annular series, all of the converging edges of said plates being of uniform lengths and provided throughout their lengths with lateral flanges, said flanges of each annular series of plates being bolted to the flanges of the adjacent annular series, whereby half the number of said flanges are pitched in one direction and the other flanges are pitched in the other direction, said plates being so positioned that any of said flanges of any plate lies throughout its length against the full length of an adjacent flange of an adjacent plate, whereby half the number of said flanges jointly form continuous reinforcing members pitched in one direction and the other flanges jointly form continuous reinforcing members pitched to the same extent in the other direction to effectively brace the structure. 

